MCQs on Coordination Compounds – CBSE Chemistry Class 12
MCQs on Coordination Compounds – CBSE Class 12 Chemistry
Inorganic Chemistry | NCERT-Based | MCQs with Answers & Explanations
The following 50 Multiple Choice Questions (MCQs) are strictly based on the NCERT syllabus for CBSE Class 12 Chemistry.
They are arranged section-wise to cover definitions, nomenclature, bonding theories, isomerism, stability, and applications of coordination compounds, with clear concept-based explanations suitable for board exam preparation.
Section A: Basic Concepts & Terminology
Q1. A coordination compound consists of:
A. Only metal ions
B. Only ligands
C. A central metal atom/ion surrounded by ligands
D. Only covalent bonds
Answer: C
Explanation:
A coordination compound contains a central metal atom or ion bonded to surrounding ligands through coordinate bonds.
Q2. The species that donate a lone pair of electrons to the metal ion are called:
A. Central ions
B. Ligands
C. Counter ions
D. Chelates
Answer: B
Explanation:
Ligands act as Lewis bases, donating electron pairs to the metal ion.
Q3. The number of ligand donor atoms bonded to the central metal ion is called:
A. Oxidation number
B. Coordination number
C. Valency
D. Atomicity
Answer: B
Explanation:
Coordination number indicates the total number of coordinate bonds formed by the metal.
Q4. Which of the following is a bidentate ligand?
A. NH₃
B. H₂O
C. CN⁻
D. C₂O₄²⁻
Answer: D
Explanation:
Oxalate ion (C₂O₄²⁻) donates two pairs of electrons to the metal.
Q5. Which ligand is ambidentate?
A. NH₃
B. EDTA⁴⁻
C. NO₂⁻
D. OH⁻
Answer: C
Explanation:
NO₂⁻ can bind through nitrogen or oxygen, showing ambidentate behavior.
Section B: Nomenclature of Coordination Compounds
Q6. In naming coordination compounds, the cation is named:
A. After the anion
B. Before the anion
C. Separately
D. Last
Answer: B
Explanation:
As per IUPAC rules, the cation is named before the anion.
Q7. The suffix “-ate” is used for the metal when the complex ion is:
A. Neutral
B. Positive
C. Negative
D. Paramagnetic
Answer: C
Explanation:
When the complex ion is an anion, the metal name ends with “-ate”.
Q8. What is the IUPAC name of [Cu(NH₃)₄]SO₄?
A. Tetraammine copper sulphate
B. Tetraamminecopper(II) sulphate
C. Copper tetraammine sulphate
D. Ammine copper sulphate
Answer: B
Explanation:
Oxidation state of Cu is +2, so the correct name is tetraamminecopper(II) sulphate.
Q9. The oxidation number of iron in [Fe(CN)₆]⁴⁻ is:
A. +2
B. +3
C. +4
D. +6
Answer: A
Explanation:
Each CN⁻ is −1. Total = −6.
Let oxidation state = x
x − 6 = −4 → x = +2
Q10. Which ligand is named as “aqua” in nomenclature?
A. NH₃
B. OH⁻
C. H₂O
D. O²⁻
Answer: C
Explanation:
H₂O ligand is named aqua.
Section C: Isomerism in Coordination Compounds
Q11. Isomerism shown by coordination compounds is mainly due to:
A. Variable oxidation states
B. Different spatial arrangements
C. Metallic bonding
D. High atomic mass
Answer: B
Explanation:
Different arrangements of ligands lead to structural and stereoisomerism.
Q12. Which of the following shows geometrical isomerism?
A. [Ag(NH₃)₂]⁺
B. [Pt(NH₃)₂Cl₂]
C. [Fe(CN)₆]⁴⁻
D. [Co(NH₃)₆]³⁺
Answer: B
Explanation:
Square planar complexes like [Pt(NH₃)₂Cl₂] show cis–trans isomerism.
Q13. Optical isomerism is shown by compounds that are:
A. Planar
B. Symmetrical
C. Chiral
D. Ionic
Answer: C
Explanation:
Optical isomerism arises in chiral (non-superimposable mirror image) complexes.
Q14. Which complex shows optical isomerism?
A. [Co(en)₃]³⁺
B. [Pt(NH₃)₄]²⁺
C. [Ni(CO)₄]
D. [Zn(NH₃)₄]²⁺
Answer: A
Explanation:
[Co(en)₃]³⁺ has no plane of symmetry, hence shows optical isomerism.
Q15. Linkage isomerism occurs due to:
A. Different oxidation states
B. Different ligands
C. Different donor atoms of ambidentate ligands
D. Different coordination numbers
Answer: C
Explanation:
Ambidentate ligands attach through different atoms, causing linkage isomerism.
Section D: Bonding in Coordination Compounds
Q16. Werner’s theory explains:
A. Magnetic properties
B. Isomerism
C. Conductance
D. Bond energies
Answer: B
Explanation:
Werner’s theory successfully explained primary and secondary valencies and isomerism.
Q17. According to Werner, secondary valency is:
A. Ionisable
B. Fixed and directional
C. Non-directional
D. Variable
Answer: B
Explanation:
Secondary valencies correspond to coordination number and have fixed geometry.
Q18. Valence Bond Theory explains bonding using:
A. Molecular orbitals
B. Hybridisation of metal orbitals
C. Ionic bonds only
D. Resonance
Answer: B
Explanation:
VBT explains coordination compounds through hybridisation of metal orbitals.
Q19. Which hybridisation corresponds to octahedral geometry?
A. sp²
B. dsp²
C. d²sp³
D. sp³
Answer: C
Explanation:
Octahedral complexes show d²sp³ hybridisation.
Q20. Inner orbital complexes are formed by:
A. Weak field ligands
B. Strong field ligands
C. Neutral ligands
D. Anionic ligands
Answer: B
Explanation:
Strong field ligands cause pairing, forming inner orbital complexes.
Section E: Crystal Field Theory & Magnetic Properties
Q21. Crystal Field Theory explains color due to:
A. Charge transfer
B. d–d transitions
C. Atomic excitation
D. Nuclear reactions
Answer: B
Explanation:
Color arises from electronic transitions between split d-orbitals.
Q22. Which ligand causes maximum crystal field splitting?
A. I⁻
B. Br⁻
C. NH₃
D. CN⁻
Answer: D
Explanation:
CN⁻ is a strong field ligand.
Q23. High spin complexes are formed by:
A. Strong field ligands
B. Weak field ligands
C. Neutral ligands only
D. Chelating ligands
Answer: B
Explanation:
Weak field ligands do not pair electrons, resulting in high spin complexes.
Q24. Which complex is paramagnetic?
A. [Fe(CN)₆]⁴⁻
B. [Co(NH₃)₆]³⁺
C. [Ni(CO)₄]
D. [Mn²⁺]
Answer: D
Explanation:
Mn²⁺ has five unpaired electrons, hence paramagnetic.
Q25. Magnetic moment depends on:
A. Atomic number
B. Oxidation state
C. Number of unpaired electrons
D. Molecular mass
Answer: C
Explanation:
More unpaired electrons → higher magnetic moment.
Section F: Stability & Applications
Q26. Chelate complexes are more stable because of:
A. Large size
B. Ring formation
C. Ionic bonding
D. High electronegativity
Answer: B
Explanation:
Chelation forms stable ring structures, increasing stability.
Q27. EDTA is an example of:
A. Monodentate ligand
B. Bidentate ligand
C. Hexadentate ligand
D. Ambidentate ligand
Answer: C
Explanation:
EDTA donates six pairs of electrons.
Q28. Haemoglobin is an example of:
A. Coordination compound
B. Double salt
C. Alloy
D. Electrolyte
Answer: A
Explanation:
Iron is coordinated to nitrogen atoms in porphyrin ring.
Q29. Which complex is used in cancer treatment?
A. Cisplatin
B. KMnO₄
C. AgNO₃
D. FeSO₄
Answer: A
Explanation:
Cisplatin is an important anticancer coordination compound.
Q30. Which coordination compound is used in photography?
A. K₄[Fe(CN)₆]
B. [Ag(NH₃)₂]⁺
C. [Cu(NH₃)₄]²⁺
D. [Co(en)₃]³⁺
Answer: B
Explanation:
Silver–ammonia complex is used in fixing photographic films.
Section G: NCERT-Based Mixed MCQs
Q31. Which complex ion is square planar?
A. [Ni(CO)₄]
B. [Pt(NH₃)₄]²⁺
C. [Fe(CN)₆]³⁻
D. [Co(NH₃)₆]³⁺
Answer: B
Explanation:
d⁸ metal ions like Pt(II) form square planar complexes.
Q32. Which ligand is neutral?
A. CN⁻
B. OH⁻
C. NH₃
D. Cl⁻
Answer: C
Explanation:
NH₃ is a neutral ligand.
Q33. Which compound shows coordination isomerism?
A. [Co(NH₃)₆]Cl₃
B. [Pt(NH₃)₂Cl₂]
C. [Cr(H₂O)₆]Cl₃
D. [Co(NH₃)₅Cl]SO₄
Answer: D
Explanation:
Exchange of ligands between cation and anion leads to coordination isomerism.
Q34. Which metal ion forms maximum coordination number?
A. Fe²⁺
B. Cu²⁺
C. Al³⁺
D. Zn²⁺
Answer: A
Explanation:
Fe²⁺ commonly shows coordination number 6.
Q35. Which complex does not show isomerism?
A. [Co(en)₃]³⁺
B. [Pt(NH₃)₂Cl₂]
C. [Ni(CO)₄]
D. [Cr(H₂O)₆]³⁺
Answer: C
Explanation:
[Ni(CO)₄] is tetrahedral and symmetrical, so no isomerism.
Q36. Which ligand forms the strongest complex with Fe³⁺?
A. F⁻
B. Cl⁻
C. NH₃
D. CN⁻
Answer: D
Explanation:
CN⁻ is a strong field ligand with high affinity.
Q37. The coordination number of cobalt in [Co(NH₃)₅Cl]²⁺ is:
A. 4
B. 5
C. 6
D. 3
Answer: C
Explanation:
Five NH₃ + one Cl⁻ → coordination number 6.
Q38. Which theory explains the magnetic behavior best?
A. Werner theory
B. Valence bond theory
C. Crystal field theory
D. Molecular orbital theory
Answer: C
Explanation:
CFT explains spin states and magnetism clearly.
Q39. Which ligand increases stability the most?
A. Monodentate
B. Bidentate
C. Polydentate
D. Neutral
Answer: C
Explanation:
Polydentate ligands form chelate complexes, increasing stability.
Q40. Which coordination compound is used in electroplating?
A. K₄[Fe(CN)₆]
B. K[Ag(CN)₂]
C. [Cu(NH₃)₄]²⁺
D. [Ni(CO)₄]
Answer: B
Explanation:
Potassium argentocyanide is used in silver electroplating.
Q41. Which complex is diamagnetic?
A. [Fe(CN)₆]⁴⁻
B. [Mn(H₂O)₆]²⁺
C. [Cu(H₂O)₆]²⁺
D. [CoF₆]³⁻
Answer: A
Explanation:
Strong field CN⁻ causes pairing → no unpaired electrons.
Q42. The color of coordination compounds is absent when:
A. Ligand is neutral
B. Metal ion has d⁰ or d¹⁰ configuration
C. Complex is ionic
D. Geometry is tetrahedral
Answer: B
Explanation:
No d–d transitions occur in d⁰ or d¹⁰ systems.
Q43. Which complex shows ionisation isomerism?
A. [Co(NH₃)₅Br]SO₄
B. [Pt(NH₃)₄]Cl₂
C. [Ni(CO)₄]
D. [Cr(H₂O)₆]Cl₃
Answer: A
Explanation:
Exchange between counter ion and ligand causes ionisation isomerism.
Q44. Which metal commonly forms low spin complexes?
A. Mn
B. Fe
C. Co
D. Zn
Answer: C
Explanation:
Co³⁺ with strong ligands often forms low spin complexes.
Q45. The coordination number of platinum in cisplatin is:
A. 2
B. 4
C. 6
D. 8
Answer: B
Explanation:
Cisplatin has square planar geometry with coordination number 4.
Q46. Which ligand is strongest in spectrochemical series?
A. H₂O
B. NH₃
C. NO₂⁻
D. CN⁻
Answer: D
Explanation:
CN⁻ causes maximum splitting of d-orbitals.
Q47. Which metal is present in vitamin B₁₂?
A. Iron
B. Magnesium
C. Cobalt
D. Zinc
Answer: C
Explanation:
Vitamin B₁₂ contains cobalt as the central metal.
Q48. Which complex has octahedral geometry?
A. [Ni(CO)₄]
B. [Pt(NH₃)₄]²⁺
C. [Fe(CN)₆]³⁻
D. [Ag(NH₃)₂]⁺
Answer: C
Explanation:
Six ligands around Fe³⁺ give octahedral geometry.
Q49. Which compound is a double salt, not a coordination compound?
A. Mohr’s salt
B. K₄[Fe(CN)₆]
C. [Cu(NH₃)₄]SO₄
D. [Co(en)₃]Cl₃
Answer: A
Explanation:
Mohr’s salt dissociates completely into ions in solution.
Q50. Coordination compounds are important in biological systems because:
A. They are colorful
B. They are ionic
C. Metals bind selectively with ligands
D. They are unstable
Answer: C
Explanation:
Selective metal–ligand interactions are essential for enzymes and biomolecules.
✅ CBSE Exam Note:
This MCQ set is 100% NCERT-aligned, concept-focused, and ideal for Class 12 board exams, revision tests, and competitive exam fundamentals.